Think of the higgs boson particle, we know it exists by how the particles around it react. Pictures and videos just don't cut it, we want something solid. I think instead of trying to find a "ghost" we look at the world around said phenomena. We look at ghosts and think supernatural but maybe we should look and say "multiverse?"
Ghosts and the supernatural do exist, as a christan I beleive ghosts are lost or evil dead people that neither heaven nor hell will acccept. I think if welcome them they will show themseves but on the other had I think exorcisims are very neccesssary for evil spirits I beleve ghosts and the supernatural exist. I wish scientist could prove it.
About the physical. What makes a person who they are is stored in their brain. A ghost would have no access to the brain, not to mention the brain is dead so would be of no help anyway. They also would not have any way to sense the world around them, i.e. eyes.
What I find so funny is the use of EMF detectors on those silly ghost hunting shows. In the real world, they are used by people like electricians to detect an electrical current. Everything electronic, even a digital wrist watch has an electromagnetic field (EMF). With all the microphones, lighting, cameras and other electrical devices being used around the detector, I would be surprised if the thing did not go off.
The frequency experiments relating to how sound can effect and induce fear, the atmospheric experiments relating to those "cold spots", and the experiments relating to producing certain elements such as images and then seeing how they effect your perception up to a day later of various phenomena are all known.
If they ever are shown to exist, then all the power to it. But until then, I do not consider that anyone has ever really seen a ghost. This is not a problem with the experiments we do, it's just a problem of existence. Here's six more words and goodnight.
Physical phenomena can only be tested physically. We can experiment with every type of input currently known to man. The important factor is to set aside our predetermined ideas of what causes "ghosts" and try and figure out the reality of the situation, not what we might want it to be.